I have seen people make their own cyclones for DC. My question is, if I wanted to make one for a staionary DC system does the cyclone have to have a certain height and diameter to be most effective. If so, who can tell me what the measurements might be…..Drew

7 replies so far

Visit Pentz's site for sure, and my advice would be to follow his design. I believe you can buy precut metal kits from his son if you want to skip some of the work, but his design will give you the optimal separation of all the dust and particles.

Be careful, you can get lost on the Bill Pentz site for a long time and still come out confused, or perhaps over informed.Shopnotes had a simple cyclone and filter cabinet plan in an old issue, perhaps a bit more colour by numbers if you didn’t want to get so in depth. But then, as others have said, for the cyclone to be truly efficinet you would need to run the calcs for your set up and dimension accordingly. Like CR1 suggests overbuild or alternatively build something simpler, like a thien separator .. Many have had very good results and it’s far more straight forward.

For a general purpose cyclone approximate dimensions are (see Fig.):a/D = 0.5, b/D = 0.25, De/D = 0.5, S/D = 0.6, h/D = 1.75, H/D = 3.75, B/D = 0.4. De could roughly match your existing DC conduits. From there you can calculate the rest of the dimensions. For high efficiency the body should be longer and narrower with smaller inlet and outlet, for high throughput the opposite.

Considering the constraints (specific DC that you already have) the cyclone cannot be overbuilt because practical efficiency in this case is a single peak function. I.e. it’s a compromise between separation efficiency (which you want to maximize) and through flow (which you want to keep above certain minimum). Keep in mind that there is no single design, which performs best for all dust collection situations.

Thank you all for your insight. My CFM will close to 1250 so it should be close to all your designs.
Kizerpea – I will be taking good notes and will be contacting you with some questions later, Thanks!Viktor – Thank you for the calculation formula, this should prove most helpful!

cr1- Holy Crap, I never saw so many freaking numbers and equations in my life, even when I was in college physics. I am not a physics person so I guess I will wing it as best I can. The above links for Bill Pentz will help a great deal but it is still alot of thought.